A multiple family group (MFG) is a family-centered, group delivered, evidence-informed, manualized intervention that targets the most common reason for referral to publicly funded clinics: youth oppositional defiant and conduct disorders. MFGs target family factors which have been consistently implicated in the onset and maintenance of childhood behavioral disorders and integrate components of existing evidence-based practices (EBPs). The MFG service delivery model was developed in collaboration with urban parents and service providers to address the serious challenges associated with EBP roll-outs: low rates of family involvement; poor uptake by providers; clinic and provider impediments to maintaining fidelity; and attenuated child outcome effects. The proposed study, in response to RFA 15-320, Clinical Trials to Test the Effectiveness of Treatment, Preventative, and Services Interventions, will employ a mixed methods Type II effectiveness-implementation hybrid research design. In collaboration with the NYS Office of Mental Health (OMH), this longitudinal study will be conducted across the NYC OMH licensed child behavioral health clinic system (n=134). We will use mixed methods, and involve 268 providers and 2,688 adult caregivers of youth (7 to 11 years). The following Specific Aims guide this study: To examine 1) short-term and longitudinal impact of MFGs on urban youth with ODD and CD (replication); 2) family-level mediators (e.g. parenting, family process) of child outcomes; 3) clinic (readiness to adopt an innovation, leadership support and climate) and provider level moderators (preparedness, motivation and fidelity) of MFG implementation and integration and; 4) the impact of CITs on clinic and provider level moderators of MFG implementation and integration. In this RCT, clinics will be stratified by borough (Manhattan, Queens, Bronx, Brooklyn, Staten Island) and randomly assigned within borough to 3 study conditions: 1) MFG+CITs; 2) MFG (with standard research training and consultation) or; 3) Standard Care. Data will be collected baseline, 8 and 16 weeks and 6 mo. follow-up) in Phase 1 (focus on implementation) and Phase II (integration). Our team includes the highest level of NYSOMH research and policy leadership. McKay and Hoagwood are the co-Directors of the NYS Clinic Technical Assistance Center, the NIMH-funded Advanced Center on Implementation of Evidence-based Practice for Children in State Systems (IDEAS; P30 MH09032) and the Center for Collaborative Urban Child Mental Health Services Research (CCCR; P20 MH085983). Advanced methodological expertise (Jaccard, Palinkas) and policy (Hogan, Bradbury, Goldman) consultation from IDEAS/CCCR Center advisors position the study for maximum public health impact. This team is uniquely prepared to build on an existing research and service infrastructure within a state public mental health system to conduct this study. Because of the nationally- focused centers and the partnerships with NYSOMH, the findings from this study are immediately actionable.